1. Field of the Invention
This invention relates generally to wireless and long distance carriers, Internet Service Providers (ISPs), and information content delivery services/providers and long distance carriers. More particularly, it relates to location services for the wireless industry.
2. Background of Related Art
Area event based location services have been defined in multiple standards, for example, Secure User Plane Location (SUPL) has been defined in Open Mobile Alliance (OMA) and Control Plane Location Services specified in 3rd Generation Partnership Project (3GPP).
A method was introduced by the same inventors as herein in U.S. Pat. No. 7,764,961, which resolves the issue where a request for area watching service was initiated when the target mobile was not served by the Home mobile network. This invention expands the concept of U.S. Pat. No. 7,764,961 to improve the overall efficiency and feasibility of area watching services when the target mobile is not in the region of the defined watched area, and it is applicable to not only the Control Plane based location service solutions (e.g. 3GPP defined location service architecture) but also User Plane based location service solutions (e.g. OMA SUPL). U.S. Pat. No. 7,764,961 is expressly incorporated herein by reference.
An area watching (a.k.a. Area Event Triggered) request may describe a watched area in three different formats: geodetic shapes, mobile network identifier, and well known location name (e.g. Seattle). Except the scenario where mobile network identifier is used, the location server (normally it is the location server that covers the specified watched area, or optimization of the location server of the home network may be applicable), needs to either covert the watched area to a set of identifiers of the radio access network (e.g. Cell Identifiers) or a geodetic description that describes the watched area. For both conversions, a Geographic Information System (GIS) is required, where the conversion from geodetic shape to access network identifiers requires the detailed geographic maps of the radio network deployments (e.g. the geographic coverage of each mobile radio base station), the database that maintains the maps is normally known as a Cell Database. Besides the fact that a GIS system is extremely expensive and complex, the size of a Cell Database has been expanding along with the development of the mobile communication technologies, e.g., in reverse proportion to cell sizes become smaller and smaller for better radio coverage. Additionally, more radio access technologies adds to the size of the Cell Database, e.g., each new access technology introduces a new base station type and new network identifier (i.e. Cell Identifier) to be included. For example, OMA SUPL has defined information elements for GSM cell, WCDMA/TD-SCDMA cell, CDMA cell, HRPD cell, LTE cell, UMB cell, WLAN AP, WiMAX BS, etc. When an area watching request includes a watched area specified in a geodetic shape, if the network directly sets up a triggered location service with a geodetic location shape due to no GIS system being available or the cell database doesn't contain complete coverage for the watched area (thus the conversion to a set of cell identifiers is not possible), the mobile has to perform positioning on a periodic basis to detect the area event (e.g. detecting if/when the mobile device enters the watched area). But in this scenario, lots of network traffic is generated for a single area watching request, and as a result the battery of the mobile device may be drained more quickly caused by the need for more frequent positioning. Moreover, the actual area watching event may be missed if the area event occurs within the time interval between positions.
The conventional extended procedure allows the location service system to use some public information to substitute the original watched area with some high level network identifiers (e.g., a mobile network identifier and a mobile switch center (MSC) identifier), and start a positioning procedure for the original watched area only when the mobile device is close to the original watched area. The procedure is generic and applicable for both Control Plane based solutions and User Plane based solutions. However, conventional systems are disadvantageous because they are inefficient, and excessively consume battery power thus limiting the amount of service (and may cause rejection of a deferred area event location service in roaming scenarios).